The present invention relates to a wobble yoke mechanism for use in a reciprocating piston machine or other positioning device. Such a machine may be for example, a pump, a refrigerator, a compressor, an internal combustion engine or other engine e.g. a Stirling engine. Such a machine may also include a positioning ram(s) for devices requiring precise positioning, e.g. a satellite dish. The axes of the piston(s) need not be parallel with a drive shaft (if present).
An object of the invention is the provision of a compact mechanism to convert reciprocating motion to rotary motion (or vice versa). The pistons drive through a wobble yoke mechanism which eliminates the need for slides, gears and multi-degree of freedom joints.